From 9f3bd2994c30df430c1aef5a8d6893ce61ee3f43 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 8 Oct 2007 22:07:16 +0000
Subject: [PATCH] Faster test for overflow in str2txid, from Marko.
---
contrib/txid/txid.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/contrib/txid/txid.c b/contrib/txid/txid.c
index 606fb40040b..015e1fb9368 100644
--- a/contrib/txid/txid.c
+++ b/contrib/txid/txid.c
@@ -234,24 +234,27 @@ static txid
str2txid(const char *s, const char **endp)
{
txid val = 0;
+ txid cutoff = MAX_TXID / 10;
+ txid cutlim = MAX_TXID % 10;
for (; *s; s++)
{
- txid last = val;
+ unsigned d;
if (*s < '0' || *s > '9')
break;
-
- val = val * 10 + (*s - '0');
+ d = *s - '0';
/*
* check for overflow
*/
- if (val > MAX_TXID || (val / 10) != last)
+ if (val > cutoff || (val == cutoff && d > cutlim))
{
val = 0;
break;
}
+
+ val = val * 10 + d;
}
if (endp)
*endp = s;
--
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